Mechanical stoker



INVENTORS fr,

4 .Sheets-Sheet 1 l BY 5:?" col H6441.,

MTORMEYQ1 Feb. 20, 1940: L. cAMPBELL. JR.. :'r An.

MECHANICAL sToxER F'ilednec. 1. 19:57

Feb. zo, 1940.

MECHANICAL sToxER Filed Dec. l, 1937 4 Sheets-Sheet. 2

ATTORNEYJ Feb. 20, 1940. l.. CAMPBELL. JR.; ET AL MEcHANcAL sToxER Filed Dec. i. 1957 4 sheets-sheet 4' ATTORNEYQJ7 Patented Feb. 20, l1940 UNITED STATES 2,191,210 MEcnAmcALsroxEn Lorn Campbell, Jr. and Anthony von Haase, Lakewood, Ohio, assignors, by mesne assignments, to

said Campbell, Jr.

Application December 1, 1937, Serial No. 177,641

Claims.

This invention relates to stokers and has for its objects to provide a. portable device of this kind which is capable of being used in connection with existing furnaces, which is of a construction to 5 prevent ignition of fuel in the stoker itself, which will not grind or break the fuel inthe feeding process and which need not contain or be associated with any forced draft mechanism.

More limited objects are to provide a simple, practical and smoothly operating stoker of the overfeed type' wherein the coal or similar fuel is catapulted from the stoker into the furnace, to provide for adjustment of the catapulting mechanism so as to vary the catapulting force and the langular position of the fuel holding element at which the fuel is projected therefrom whereby to vary the trajectory of the fuel to accommodate the device to existing furnaces of differing cony struction such as different sizes of furnace feed doors and different lengths of feed extensions between the repot and the furnace door as well as for directing the fuel to a selecteddesirable point in iirepots of different sizes, and to provide for sudden arrest of the fuel holding element from a high velocity whereby to discharge the fuel cleanly in a compact mass and avoid excessive scattering. Y

A further object is to provide an auinliary feeding element preferably operated in timed relation with the catapulting device and adapted to feed fuel from4 the storage hopper and assist in loading the catapulting device, such auxiliary feed -means preferably being adjustable as to length of stroke.

A further and very important object of the invention is to provide for actual or substantial contact of a fuel receiving element of the catapulting device with the fuel supporting surface from .a point in advance of its engagement'withdthe fuel mass whereby to prevent breaking or grinding of fuel Aparticles or wedging thereof between the fuel receiving element and the fuel supporting surface.

A still further object is to provide a novel and superior drive for the catapulting device, the same being of such construction as to move the fuel receiving part of such catapulting device by a yielding drive at a low rate of speed while'it is being loaded and elevated n throwing position whereby to avoid excessive motor load due to lumps while the fuel receiving device is leaving the fuel heap after being loaded, a `d to cause it to be suddenly and greatly accelerated through a portion of its revolution and then si. 'idenly arrested whereby to project ythe fuel into the fire- (Cl- 11o- 115) box of the furnace and thereafter to move slowly until the catapulting portion of the next revolution is again reached. An important feature of the device disclosed is its, light Weight construction combined with portability whereby it readily can be wheeled into position at the furnace or removed therefrom and wheeled to the c'oal bin for filling. Also, it can be easily pulled away for access to the furnace for starting a fire or for removal of ashes. Other and more limited objects will bein part apparent and in part pointed out hereinafter in connection with the accompanying drawings wherein Fig. 1 is a diagrammatic `transverse section through a furnace of usual construction and showing our improved stoker in operative relation thereto; Fig. 2 is a section on the line 2-2 of Fig. l, showing the full receiving element or shovel in its fuel-distributing position; Fig. 3 is an enlarged fragmentary section taken on the same plane as Fig. 2; Fig. 4 is an enlarged section on the line 4-4 of Fig. 3; Fig. 5 is a section on the line 5-5 of Fig. 3v; Fig. 6 is an enlarged section on the line 6-6 of Fig. 1; Fig. 7 is a detail perspective of one end of a sleeve carrying the fuel holding element of the catapulting device; Fig. 8 is a perspective of a trigger element cooperating with said sleeve and a cam on the power i shaft; and Fig. 9 a detail in section showing a modification of the shovel.

General construction and operation In the drawings, the numeral I0 indicates gen'- erally a furnace of usual construction having a repot II opening through a projection or feeding neck I2 to the exterior. The door normally closing the outer end of the feeding neck I2 is shown as having been opened and our improved y stoker is shown as it would appear after having been pushed into position to close the door opening. The stoker comprises a supporting base I3 housing the driving motor (which may be electric, hydraulic, or the like) and which is mounted lon vertically adjustable legs I4 resting oncasters Il, avhopper portion I5 adapted to contain a charge of fuel, a feed chamber I6 separated from the hopper I5 by a heat insulating baille I1, a connecting neck I8 adapted to connect the feed chamber I6 in communication with the fuel neck I2 of the furnace, and feed means comprising a catapulting device indicated generally by the numeral I9 and an auxiliary feeding device 20.

In operation, the hopper I5 is supplied with coal, or similar lmnp or granular fuel, the largest particles of which are of a size readily to pass 55 2 f nace.- `If the shovelwere free to 'swing past the'v 'f scattering and excessive piling 'up fuel .in -the between the lower end of the baille I1, comprising spaced plates to provide heat insulation and cooling and thereby prevent fuel in the hopper from sticking, and the auxiliary feed slide 26, and the driving motor for the catapulting device I9 is started. The device I9 includes a rotating fuel receiving or shovel element indicated generally by the numeral 2| which rotates in a. counterclockwise direction, as seen in Fig. 1. Responsive to operation of the motor, the shovel 2| rotates, coming into contact or substantial contact with the bottom wall 22 of the feed chamber I6 at approximately the level of its axis of rotation and moving in contact or substantial contact therewith, much in the manner of a shovel being moved along a iioor, until it has received a load of fuel. The slide 20 preferably is so timed as to move toward the left to its extreme position in that direction approximately at the time the shovel element 2| is in position to be fully loaded. The slide 26 then begins to recede while the shovel continues to vmove in a counter-clockwise direction until it reaches approximately the point which it occupies in Fig. 1 whereupon it stops while the projecting means is being conditioned to impart -a sudden acceleration which projects the fuel into the firepot.

Catdpultng device 'supported by Journals w and :ab carried by the side walls of the feed chamber I6 is a power shaft 24which isdriven by an electric motor 25 supported on a plate 25L through the medium of a gear reduction means comprising reducing gear mechanisms at 26 and 26 connected by a shaft 26b and protected by a cover 26. Keyed on the shaft 24 is a drum 21 on the outside of which is received a helical spring 28 one end of which is connected to said drum 21 as by having one end 29 received in an opening of the head 36 in such drum. Rotatable `on the shaft 24 is a sleeve 3| which carries the shovel element 2| through the medium of an arm 32 received in a suitable transverse bore in an enlarged portion 33 thereof. The other end 34 of the spring 28 is received in a suitable opening in the enlarged portion 33 of the sleeve 3|. The spring 28 isprotected by a cover sleeve 28* mounted as shown. The sleeve 3| extends to the outside of the feed chamber I6 and terminates in an enlarged portion 35 secured thereto and provided with a notch 36. Secured to the shaft 24 adjacent the portion 35 is a cam 31.. The element 23 which vcarries the journal 23" isrotatably and adjustably mounted on the wall I6* of the feed chamber I6, being held in any adjusted position by bolts 31*1l received 'in slots 315 andsuitable openings in the wall I6. Pivoted to the element 23 is a detent 38 movable through an opening 23 in the element 23 and urged by a spring 39 toward the elements 35 and 31. A portion 40 of the detent 38 rides on the element '35 and drops into the notch 36 as the sleeve 3| rotates.

The engagement of the element 40 inthe notch 35 arrests the rotation of the sleeve 3| and consequently of the shovel 2| and holdsit while the shaft 24 continues to rotate, consequently energizing the spring 28. .The spring 28 is energized by beingy unwound whereby, when it is released,

vit will wind up on the' drum 21 and bring the shovel .2| to a sudden v.stopjwhereby to cleanly and completely "discharge its loadinto the f-urdischarge point, the. load would tend' to great feed neck of' the furnace. Since the shaft 24 continues to rotate, the cam 31 will, after a predetermined interval, acting through the medium of the adjustable set screw 4|, lift the portion 40 out of the notch 36 thereby releasing the sleeve 3|. 'I'he spring 28 having been energized by unwinding will, upon the release of the element 40 from the notch 36, suddenly accelerate the rotation of the sleeve 3| and consequently the shovel 2| (the same being suddenly stopped by the re-winding of the spring) and project the fuel into the furnace. The spring being again restored to normal, the cycle just described is repeated. The adjustment of the element 23 and the adjustability of the set-screw 4| which passes through the opening 4|a in the trigger 38 make possible adjustment of the amount of unwinding of the spring 28 before the shovel is released and the point of releaseas well as the point at which the motion of the shovel is arrested by the Winding up of the spring 28 on the drum 21. The sleeve 2ligl assures even exing of the spring 26 along its whole extent and protects the moving parts which it encloses from ingress of fuel particles or dust.

Auxiliary feed riveted' on the wall or lthe reed immerv s as indicated at 42 is a lever 43 comprising a flat plate with a. bifurcatedupper end terminating in vears 44 constituting cam followers and cooperating with a cam 45 on the shaft 24. ,Upon rotation of the shaft 24 the lever 43 is oscillated thereby imparting an oscillatory motion to the lever 46 pivoted lbelow Athe oor 22 of the feed chamber `|6, as indicated at 41 and extending into an opening 48 in the lever 43. The lever 46 is provided with a slot 49 which receives a pin 50 carried by a link 5| which is in turn pivotally connected to the slide 2II, as indicated at 52, by a pin extending through a slot 52* in the bottom wall 22.

It win be obvious that by adjusting the position of the cam 46 with respect to the shaft 24,

- within the scope of the invention. It will be obvious that such resistance as the loading of the coal oders to the motion'of the shovel will tend to ex the spring 28 and that any unevenness of resistance to the motion of the shovel will tend to be smoothed out, thereby reducing the maximum power requirement and consequently the capacity requirements for the driving motor.

The stroke of the slide obviously can be varied by varying the position of the pin 58 in the slot 49. This is accomplished through the medium of a bell crank lever 53 terminating at one end in an adjusting handle 54 adapted to be engaged with any one of a plurality of teeitnot shown) and connected at its inner/end by a link 56 to the power transmitting link lI. .ff'

We prefer to make the shovel `element of the catapulting device narrower than the feed cham- Vber'i6v and at the same 'time to have it operate f, vagainst a fuel heap not substantially wider than itself. Accordingly, we provide plates 51 welded or otherwise securedzto the, bottom and side walls of the'fuel chamber and eectively narrowing the chamber, an auxiliary feeding device comprising shovel 2| to be in actual or substantial contact with the bottom wall of the feed chamber through the first part of the loading operation. The present preferred manner of accomplishing this result is to provide the shovel 2| with a resilient forward edge 58 which will be flexed by contact with the wall 22 and will resume its free position .only at or after the loading of the shovel has been completed. We have found that this construction results/in proper loading of the shovel and prevents breaking, grinding or wedging of fuel particles between the shovel and the floor of the feed chamber. Good results can be had by making the edge of the shovel non-resilientbut locating it substantially exactly far enough from the power shaft 24 to contact the curved wall 22, as shown in Fig. 9.

'I'he control for our improved stoker may be manual, semi-automatic or fully automatic and, per se, forms no part of the present invention.

From the foregoing it will be clear that we have provided a stoker well adapted fox` its intended purpose and while we have shown and described the present preferred embodiment we vwish it understood that we are not limited to the details of the disclosure but only in accordance with the appended claims.

Having thus described our invention, what we claim is: l

1. In a mechanical Stoker, in combination, a fuel chamber, a power shaft rotatable therein, a rotatable sleeve on said shaft, a yieldable connection between said shaft and said sleeve, a shovel carried by said sleeve, means for arresting the motion of said sleeve at a predetermined point in its revolution and means for releasing said sleeve arresting means at a predetermined point in the revolution of said power shaft.

2. In a mechanical stoker, the combination with a fuel chamber, a shovel therein and means for rotating the same to cause it to be loaded with fuel once each revolution, said 4last means comprising a power shaft, means forA rotating said power shaft at a low velocity, and means associ'- ated with said power shaft and operated thereby for rapidly accelerating and suddenly arresting the motion of the shovel within a limited portion of each revolution subsequent to loading thereof whereby to discharge fuel therefrom.

3. In the combination recited in claim 2, said fuel chamber being generally wider than said shovel but tapering to a width not greatly exceeding that of said shovel at the bottom in the region whereloading of the shovel is effected.

4.1In the combination recited in claim 2, a hopper connected at the bottom with the fuel a slide reciprocable along the bottom of said hopper and said fuel chamber and means for operating said slide in timed relation to said shovel and in such phase relation thereto as to be at its innermost position with respect to the fuel chamber at approximately the time when the shovel is completely loaded.

5. In the combination recited in claim 2, said shovel being provided with a resilient lip at its forward edge adapted to be flexed by contact with the bottom of the fuel chamber during the loading operation.

6. In the combination recited in claim 2, said fuel chamber having a substantially horizontal bottom portion and an upstanding wall merging with said horizontal portion by a curved portion substantially concentric with said power shaft,

said shovel being mounted at such a distance from said power shaft that its forward edge moves over said curved wall portion in substantial contact therewith.

7. In a mechanical Stoker, in combination, a fuel chamber, a power shaft rotatable therein, a rotatable sleeve on said shaft, a yieldable connection between said shaft and said sleeve, a

shovel carried by said sleeve, adjustable means for arresting motion of said sleeve at a predetermined point in its revolution and adjustable means for releasing said sleeve arresting means at a predetermined point in the revolution of said power shaft. l

8. In the combination 'recited in claim 2, an auxiliary feeding device for pushing fuel toward said shovel and means operated by said power shaft for operating said auxiliary feeding device in such timed relation to said shovel as to push fuel toward the shovel as the shovel is being loaded. y

9. In a mechanical stoker, in combination, a fuel chamber, a power shaft rotatable therein, a rotatable sleeve on said power shaft, a yieldable connection between said shaft and said sleeve, stop means carried by said sleeve, a trigger carried by said fuel chamber having a portion adapted to engage said stop means to arrest rotation of said sleeve, a cam on said power shaft, and meansl carried by said trigger adapted to be engaged by said cam for disengaging said trigger from said stop means.

10. In a mechanical Stoker, in combination, a fuel chamber, a power shaft rotatable therein, a rotatable sleeve on said power shaft, a yieldable connectionbetween said shaft and said sleeve, stop means carried by said sleeve, a trigger adjustably carried by said fuel chamber having a portion adal ted to engage said stop means to arrest rotation of said sleeve, a cam on said power LORN CANIPBELL, JR. ANTHONY VON HAASE. 

